in-between
adjective [ before noun ] uk/ˌɪn.bɪˈtwiːn/ us/ˌɪn.bɪˈtwiːn/
介于两者之间的
between two clear or accepted stages or states, and therefore difficult to describe or know exactly
He knows quite a lot of French, but he's at an in-between stage and not fluent yet. 他法语懂得不少，但他的水平不上不下，还不够流利。
Synonym: middle